1,3-dipolar compound bearing an imidazole functional group

ABSTRACT

In a 1,3-dipolar compound of formula Q-A-B, Q comprises a dipole containing at least and preferably one nitrogen atom, A, which is preferably divalent, is an atom or a group of atoms connecting Q to B, and B comprises an imidazole ring. An unsaturated polymer modified by grafting the 1,3-dipolar compound is also disclosed.

FIELD OF THE INVENTION

The field of the present invention is that of modifying agents intendedto functionalize unsaturated polymers along the polymer chain.

RELATED ART

Modifying the chemical structure of a polymer generally impacts thechemical and physical properties of the polymer, and also the propertiesof the compositions containing it. Modifying the structure of a polymer,such as the functionalization of a polymer, is particularly sought forwhen it is desired to bring together a polymer and a filler in acomposition. Chemically modifying a polymer can improve the dispersionof the filler in the polymer and can thus make it possible to obtain amore homogeneous material. In the case of certain fillers, such ascarbon black or silica, a better dispersion of the filler will generallybe reflected by a fall in hysteresis of the composition. Such a propertyis sought for, in particular in rubber compositions intended, forexample, for tyre applications. This fall in hysteresis is oftenaccompanied by a fall in the stiffness in the cured state of thecomposition, which can render the composition unsuitable for the usewhich it is desired to make of it. There thus exists a need to findmodifying agents which make it possible both to functionalize a polymerand to modify this hysteresis/stiffness in the cured state compromise ofa composition comprising a polymer and a filler.

The chemical reactions for modifying an unsaturated polymer include thereactions for grafting a compound. Known compounds for being grafted toan unsaturated polymer are, for example, 1,3-dipolar compounds, such asdescribed in Patent Applications WO 2006/045088 and WO 2012/007441. Thefirst patent application describes compounds which make possible thegrafting of an oxazoline, thiazoline, alkoxysilane or allyltinfunctional group. The second describes compounds which make possible thegrafting of nitrogen-based associative functional groups. However,neither of these patent applications describes 1,3-dipolar compoundsbearing an imidazole ring, or the grafting of an imidazole ring to anunsaturated polymer by reaction of these 1,3-dipolar compounds with theaim of modifying the hysteresis/stiffness in the cured state compromiseof a composition comprising the polymer in the presence of a filler.

BRIEF DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Thus, a first subject-matter of the invention is a 1,3-dipolar compoundcorresponding to the formula (I):Q-A-B  (I)

-   -   in which:    -   Q comprises a dipole containing at least and preferably one        nitrogen atom,    -   A, which is preferably divalent, is an atom or a group of atoms        connecting Q to B,    -   B comprises an imidazole ring corresponding to the formula (II):

-   -   in which:    -   three of the four symbols Z, Y, R and R′, which are identical or        different, each represent an atom or a group of atoms, it being        possible for Z and Y to form, together with the carbon atoms to        which they are attached, a ring,    -   and the fourth symbol Z, Y, R or R′ denotes a direct attachment        to A.

The invention also relates to a process for modifying an unsaturatedpolymer, which process comprises the reaction of a 1,3-dipolar compoundin accordance with the invention with at least one and preferablyseveral unsaturations of the unsaturated polymer.

The invention also relates to a polymer which is capable of beingobtained by the process in accordance with the invention.

I. DETAILED DESCRIPTION OF THE INVENTION

In the present description, unless expressly indicated otherwise, allthe percentages (%) shown are % by weight. The abbreviation “phr” meansparts by weight per hundred parts of elastomer (of the total of theelastomers, if several elastomers are present).

Furthermore, any interval of values denoted by the expression “between aand b” represents the range of values greater than “a” and lower than“b” (that is to say, limits a and b excluded), whereas any interval ofvalues denoted by the expression “from a to b” means the range of valuesextending from “a” up to “b” (that is to say, including the strictlimits a and b).

The term “1,3-dipolar compound” is understood according to thedefinition given by the IUPAC.

The 1,3-dipolar compound corresponds to the formula (I):Q-A-B  (I)

-   -   in which:    -   Q comprises a dipole containing at least and preferably one        nitrogen atom,    -   A, which is preferably divalent, is an atom or a group of atoms        connecting Q to B,    -   B comprises an imidazole ring corresponding to the formula (II):

-   -   in which:    -   three of the four symbols Z, Y, R and R′, which are identical or        different, each represent an atom or a group of atoms, it being        possible for Z and Y to form, together with the carbon atoms to        which they are attached, a ring (of course, when neither Z nor Y        denotes the 4^(th) symbol),    -   and just the fourth symbol denotes a direct attachment to A.

According to a first alternative form of the invention, R denotes adirect attachment to A, in which case R is the 4^(th) symbol.

According to this alternative form, R′ can be a hydrogen atom or acarbon-based group which can contain at least one heteroatom.

According to a preferred embodiment of this alternative form, R′represents a carbon-based group containing from 1 to 20 carbon atoms,preferably an aliphatic group, more preferably an alkyl group whichpreferably contains from 1 to 12 carbon atoms.

According to a second alternative form of the invention, R′ denotes adirect attachment to A, in which case R′ is the 4^(th) symbol.

According to the first or the second alternative form, Z and Y can eachbe a hydrogen atom.

According to another embodiment of the first alternative form or of thesecond alternative form, Z and Y form, together with the carbon atoms towhich they are attached, a ring. The ring formed by Z, Y and the atomsto which Z and Y are attached may or may not be substituted and cancomprise at least one heteroatom. Z and Y can form, with the two carbonatoms to which they are attached, an aromatic nucleus. In this case, theimidazole ring can be a substituted or unsubstituted benzimidazole.

According to a third alternative form of the invention, of course when Yand Z do not form, together with the carbon atoms to which they areattached, a ring, Y or Z denotes a direct attachment to A, in which caseY or Z is the 4^(th) symbol.

According to a specific embodiment of the second or of the thirdalternative form of the invention, R represents a hydrogen atom or acarbon-based group which can contain at least one heteroatom.

According to this specific embodiment of the second alternative form orof the third alternative form of the invention, R can be a group of 1 to20 carbon atoms, preferably an aliphatic group, more preferably an alkylgroup preferably containing from 1 to 12 carbon atoms, more preferablystill a methyl.

A can be a group containing up to 20 carbon atoms, which group cancontain at least one heteroatom. A can be an aliphatic or aromaticgroup.

When A is an aliphatic group, A preferably contains from 1 to 20 carbonatoms, more preferably from 1 to 12 carbon atoms, more preferably stillfrom 1 to 6 carbon atoms and very particularly from 1 to 3 carbon atoms.When A is an aromatic group, A preferably contains from 6 to 20 carbonatoms, more preferably from 6 to 12 carbon atoms.

Particularly suitable as divalent group A is an alkylene groupcontaining from 1 to 20 carbon atoms, preferably from 1 to 12 carbonatoms, more preferably from 1 to 6 carbon atoms and more preferablystill from 1 to 3 carbon atoms. Mention may be made, as divalent group Acontaining from 1 to 3 carbon atoms which is suitable, of the methylenegroup.

An arylene group preferably containing from 6 to 20 carbon atoms, morepreferably from 6 to 12 carbon atoms, may also be suitable as divalentgroup A.

Very particularly suitable as 1,3-dipolar compounds are the compoundsselected from the group consisting of nitrile oxides, nitrile imines andnitrones, in which case Q contains a —C≡N→O, —C≡N→N— or —C═N(→O)— unit.

According to the specific embodiment of the invention where Q comprisesa —C≡N→O unit, Q preferably comprises, more preferably represents, theunit corresponding to the formula (III) in which four of the fivesymbols R₁ to R₅, which are identical or different, are each an atom ora group of atoms and the fifth symbol denotes a direct attachment to A,it being known that R₁ and R₅ are both other than H. The four of thefive symbols R₁ to R₅ can be aliphatic or aromatic groups. The aliphaticgroups can contain from 1 to 20 carbon atoms, preferably from 1 to 12carbon atoms, more preferably from 1 to 6 carbon atoms and morepreferably still from 1 to 3 carbon atoms. The aromatic groups cancontain from 6 to 20 carbon atoms and preferably from 6 to 12 carbonatoms.

R₁, R₃ and R₅ are preferably each an alkyl group of 1 to 6 carbon atoms,more preferably of 1 to 3 carbon atoms, and more preferably still amethyl or ethyl group.

According to an alternative form of this specific embodiment of theinvention, R₁, R₃ and R₅ are identical. According to this alternativeform where they are identical, R₁, R₃ and R₅ are preferably each analkyl group of 1 to 6 carbon atoms, more preferably of 1 to 3 carbonatoms, and more preferably still a methyl or ethyl group.

More preferably, the 1,3-dipolar compound is the compound2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile oxide,corresponding to the formula (IIIa), or the compound2,4,6-triethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile oxide,corresponding to the formula (IIIb):

According to the specific embodiment of the invention where Q comprisesa —C═N(→O)— unit, Q preferably comprises, more preferably represents,the unit corresponding to the formula (IV) or (V):

-   -   in which:    -   Y₁ is an aliphatic group, preferably an alkyl group preferably        containing from 1 to 12 carbon atoms, or an aromatic group        containing from 6 to 20 carbon atoms, preferably an alkylaryl        group, more preferably a phenyl or tolyl group,    -   and Y₂, comprising a direct attachment to A, is an aliphatic        group, preferably an alkylene group preferably containing from 1        to 12 carbon atoms, or an aromatic group preferably containing        from 6 to 20 carbon atoms and comprising, on its benzene        nucleus, the direct attachment to A.

The direct attachment of the benzene nucleus of Y₂ to A amounts tosaying that A is a substituent of the benzene nucleus of Y₂.

According to this specific embodiment of the invention, the 1,3-dipolarcompound is the compound of formula (IVa), (IVb), (Va) or (Vb):

The process, which is another subject-matter of the invention, comprisesthe reaction of the 1,3-dipolar compound described above with at leastone and preferably several unsaturations of an unsaturated polymer.Several unsaturations is understood to mean at least two unsaturations.

The 1,3-dipolar compound can be used to modify an unsaturated polymer bya grafting reaction of the 1,3-dipolar compound with at least one andpreferably several unsaturations of the unsaturated polymer.

According to a preferred embodiment of the invention, the unsaturationsof the polymer are carbon-carbon bonds, preferably carbon-carbon doublebonds.

The grafting of the 1,3-dipolar compound is carried out by[3+2]cycloaddition of the reactive group or groups of the 1,3-dipolarcompound to one or more double bonds of a diene elastomer chain. Themechanism of the cycloaddition of a nitrile oxide, a nitrone and anitrile imine can be illustrated by the following equations, in whichthe symbol ¤ represents any substituent:

-   -   Cycloaddition of a nitrile oxide to an unsaturation or double        bond of a diene elastomer (in this instance a polyisoprene)

-   -   Cycloaddition of a nitrone to an unsaturation or double bond of        a diene elastomer (in this instance a polyisoprene)

-   -   Cycloaddition of a nitrile imine to an unsaturation or double        bond of a diene elastomer (in this instance a polyisoprene)

The grafting of the 1,3-dipolar compound can be carried out in bulk, forexample in an internal mixer or an external mixer, such as an open mill.The grafting is then carried out either at a temperature of the externalmixer or of the internal mixture of less than 60° C., followed by astage of a grafting reaction under a press or in an oven at temperaturesranging from 80° C. to 200° C., or at a temperature of the externalmixer or of the internal mixer of greater than 60° C., withoutsubsequent heat treatment.

The grafting process can also be carried out in solution. Thetemperature at which the grafting is carried out is easily adjusted by aperson skilled in the art from his general knowledge by taking intoaccount the concentration of the reaction medium, the reflux temperatureof the solvent, the thermal stability of the polymer and the 1,3-dipolarcompound. For example, a temperature in the vicinity of 60° C. may besuitable. The polymer, thus modified, can be separated from its solutionby any type of means known to a person skilled in the art and inparticular by an operation of evaporation of the solvent under reducedpressure or by a steam stripping operation.

In the grafting reaction for modifying the unsaturated polymer, the1,3-dipolar compound is reacted according to a preferred stoichiometryof between 0 and 3 molar equivalents, more preferably between 0 and 2molar equivalents, more preferably still between 0 and 1 molarequivalent, indeed even more preferably still between 0 and 0.7 molarequivalent, of imidazole ring per 100 moles of monomer unitsconstituting the polymer. For each of these preferred ranges, the lowerlimit is advantageously at least 0.1 molar equivalent of 1,3-dipolarcompound. The amount of 1,3-dipolar compound used for grafting thepolymer is expressed as molar equivalent of imidazole ring. For example,if the 1,3-dipolar compound contains just one imidazole ring of formula(II) as defined above, one mole of imidazole ring corresponds to onemole of 1,3-dipolar compound. If the 1,3-dipolar compound contains twoimidazole rings of formula (II) as defined above, two moles of imidazolering correspond to one mole of 1,3-dipolar compound. In the latter case,the use of the 1,3-dipolar compound according to one molar equivalent ofimidazole ring corresponds to a half-mole of 1,3-dipolar compound.

Preferably, whether the grafting is carried out in solution or in bulk,the polymer is antioxidized beforehand in order to prevent possibledegradation of the macrostructure of the polymer during the graftingreaction.

The unsaturated polymer to be modified exhibits at least one andpreferably several unsaturations which are capable of reacting with the1,3-dipolar compound in accordance with the invention.

The unsaturated polymer is preferably a diene polymer, more preferably adiene elastomer.

Diene polymer should be understood as meaning a polymer comprising dienemonomer units, in particular 1,3-diene monomer units.

A “diene” elastomer (or without distinction rubber) should beunderstood, in a known way, as meaning an elastomer composed, at leastin part (i.e., a homopolymer or a copolymer), of diene monomer units(monomers bearing two conjugated or non-conjugated carbon-carbon doublebonds).

These diene elastomers can be classified into two categories:“essentially unsaturated” or “essentially saturated”. Generally,“essentially unsaturated” is understood to mean a diene elastomerresulting at least in part from conjugated diene monomers having acontent of units diene origin (conjugated dienes) which is greater than15% (mol %); thus it is that diene elastomers such as butyl rubbers orcopolymers of dienes and α-olefins of EPDM type do not come within thepreceding definition and can in particular be described as “essentiallysaturated” diene elastomers (low or very low content, always less than15%, of units of diene origin). In the category of “essentiallyunsaturated” diene elastomers, the term “highly unsaturated” dieneelastomer is understood to mean in particular a diene elastomer having acontent of units of diene origin (conjugated dienes) which is greaterthan 50%.

Given these definitions, diene elastomer capable of being used in thecompositions in accordance with the invention is understood moreparticularly to mean:

(a)—any homopolymer of a conjugated diene monomer, in particular anyhomopolymer obtained by polymerization of a conjugated diene monomerhaving from 4 to 12 carbon atoms;

(b)—any copolymer obtained by copolymerization of one or more conjugateddienes with one another or with one or more vinylaromatic compoundshaving from 8 to 20 carbon atoms;

(c)—a ternary copolymer obtained by copolymerization of ethylene and ofan α-olefin having from 3 to 6 carbon atoms with a non-conjugated dienemonomer having from 6 to 12 carbon atoms, such as, for example, theelastomers obtained from ethylene and propylene with a non-conjugateddiene monomer of the abovementioned type, such as, in particular,1,4-hexadiene, ethylidenenorbornene or dicyclopentadiene;(d)—a copolymer of isobutene and isoprene (butyl rubber) and also thehalogenated versions, in particular chlorinated or brominated versions,of this type of copolymer.

Although it applies to any type of diene elastomer, a person skilled inthe art of tyres will understand that the present invention ispreferably employed with essentially unsaturated diene elastomers, inparticular of the above type (a) or (b).

In the case of copolymers of the type (b), the latter comprise from 20%to 99% by weight of diene units and from 1% to 80% by weight ofvinylaromatic units.

The following are suitable in particular as conjugated dienes:1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di(C₁-C₅alkyl)-1,3-butadienes, such as, for example, 2,3-dimethyl-1,3-butadiene,2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene or2-methyl-3-isopropyl-1,3-butadiene, an aryl-1,3-butadiene,1,3-pentadiene or 2,4-hexadiene.

The following, for example, are suitable as vinylaromatic compounds:styrene, ortho-, meta- or para-methylstyrene, the “vinyltoluene”commercial mixture, para-(tert-butyl)styrene, methoxystyrenes,chlorostyrenes, vinylmesitylene, divinylbenzene or vinylnaphthalene.

Preferably, the diene elastomer is an essentially unsaturated elastomerselected from the group consisting of polybutadienes (BRs),polyisoprenes, butadiene copolymers, isoprene copolymers and themixtures of these elastomers. Very particularly suitable as dieneelastomer is a polybutadiene (BR), a copolymer of butadiene and styrene(SBR), a natural rubber (NR) or a synthetic polyisoprene (IR) preferablyexhibiting a molar content of cis-1,4-bonds of greater than 90%.

Another subject-matter of the invention is the polymer which can beobtained by the process described according to any one of itsembodiments.

The polymer which is a subject-matter of the invention is preferably adiene polymer, preferably a diene elastomer, more preferably anessentially unsaturated diene elastomer, more preferably still anessentially unsaturated elastomer selected from the group consisting ofpolybutadienes, polyisoprenes, butadiene copolymers, isoprene copolymersand the mixtures of these elastomers.

The abovementioned characteristics of the present invention, and alsoothers, will be better understood on reading the following descriptionof several implementational examples of the invention, given by way ofillustration and without limitation.

II. IMPLEMENTATIONAL EXAMPLES OF THE INVENTION II1.1—Measurements andTests Used

NMR Analysis:

The structural analysis and also the determination of the molar puritiesof the molecules synthesized are carried out by an NMR analysis. Thespectra are acquired on a Bruker Avance 3400 MHz spectrometer equippedwith a 5 mm BBFO Z-grad “broad band” probe. The quantitative ¹H NMRexperiment uses a simple 30° pulse sequence and a repetition time of 3seconds between each of the 64 acquisitions. The samples are dissolvedin a deuterated solvent, deuterated dimethyl sulphoxide (DMSO), unlessotherwise indicated. The deuterated solvent is also used for the locksignal. For example, calibration is carried out on the signal of theprotons of the deuterated DMSO at 2.44 ppm with respect to a TMSreference at 0 ppm. The ¹H NMR spectrum coupled with the 2D ¹H/¹³C HSQCand ¹H/¹³C HMBC experiments make possible the structural determinationof the molecules (cf. tables of assignments). The molar quantificationsare carried out from the quantitative 1D ¹H NMR spectrum.

The determination of the molar content of grafted nitrile oxide compoundis carried out by an NMR analysis. The spectra are acquired on a 500 MHzBruker spectrometer equipped with a “5 mm BBFO Z-grad CryoProbe”. Thequantitative ¹H NMR experiment uses a simple 30° pulse sequence and arepetition time of 5 seconds between each acquisition. The samples aredissolved in deuterated chloroform (CDCl₃) with the aim of obtaining alock signal.

2D NMR experiments have made it possible to confirm the nature of thegrafted unit by virtue of the chemical shifts of the carbon and protonatoms.

II.2—Synthesis of the 1,3-dipolar Compound2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile Oxide

This compound can be prepared according to the following reactionscheme:

II.2-1—Synthesis of 2-(chloromethyl)-1,3,5-trimethylbenzene

This compound can be obtained according to a procedure described in thefollowing paper: Zenkevich, I. G. and Makarov, A. A., Russian Journal ofGeneral Chemistry, Vol. 77, No. 4 (2007), pp. 611-619 (Zhurnal ObshcheiKhimii, Vol. 77, No. 4 (2007), pp. 653-662).

A mixture of mesitylene (100.0 g, 0.832 mol), paraformaldehyde (26.2 g,0.874 mol) and hydrochloric acid (240 ml, 37%, 2.906 mol) in acetic acid(240 ml) is stirred and heated very slowly (1.5 hours) up to 37° C.After returning to ambient temperature, the mixture is diluted withwater (1.0 l) with CH₂Cl₂ (200 ml) and the product is extracted withCH₂Cl₂ (4 times with 50 ml). The organic phases are combined, thenwashed with water (5 times with 100 ml) and evaporated down to 11-12mbar (temperature of the bath=42° C.). A colourless oil (133.52 g, yield95%) is obtained. After 15-18 hours at +4° C., the oil crystallized. Thecrystals are filtered off, washed with petroleum ether cooled to −18° C.(40 ml) and then dried under atmospheric pressure at ambient temperaturefor 3 to 5 hours. A white solid (95.9 g, yield 68%) with a melting pointof 39° C. is obtained. The molar purity is greater than 96% (¹H NMR).

No. δ ¹H (ppm) δ ¹³C (ppm) 1/8 2.27 18.4 2/7 — 136.9 3/6 6.81 128.5 4 —137.4 5 2.15 20.3 9 — 130.5 10  4.69 41.3

II.2-2—Synthesis of 3-(chloromethyl)-2,4,6-trimethylbenzaldehyde

This compound can be obtained according to a procedure described in thefollowing paper: Yakubov, A. P., Tsyganov, D. V., Belen'kii, L. I. andKrayushkin, M. M., Bulletin of the Academy of Sciences of the USSR,Division of Chemical Science (English Translation), Vol. 40, No. 7.2(1991), pp. 1427-1432 (Izvestiya Akademii Nauk SSSR, SeriyaKhimicheskaya; No. 7 (1991), pp. 1609-1615).

A solution of 2-(chloromethyl)-1,3,5-trimethylbenzene (20.0 g, 0.118mol) and dichloromethyl methyl ether (27.26 g, 0.237 mol) indichloromethane (200 ml) is added under argon over 10-12 minutes to asolution of TiCl₄ (90.0 g, 0.474 mol) in dichloromethane (200 ml) at 17°C. After stirring at 17-20° C. for 15-20 minutes, water (1000 ml) andice (500 g) are added to the reaction medium. After stirring for 10-15minutes, the organic phase is separated. The aqueous phase is extractedwith CH₂Cl₂ (3 times with 75 ml). The combined organic phases are washedwith water (4 times with 100 ml) and evaporated under reduced pressureto result in a solid (temperature of the bath=28° C.). The targetproduct (22.74 g) is obtained with a yield of 97%, with a melting pointof 58° C. The molar purity, estimated by ¹H NMR, is 95 mol %.

No. δ ¹H (ppm) δ ¹³C (ppm) 1 4.77 40.6 2 — 132.9 3 — 139.5 4 2.51 14.4 5— 131.4 6 10.43  194.2 7 — 140.1 8 2.41 19.3 9 6.99 131.2 10 — 142.4 112.34 19.8

II.2-3—Synthesis of2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzaldehyde

A mixture of 3-(chloromethyl)-2,4,6-trimethylbenzaldehyde (10.0 g, 0.051mol) and imidazole (10.44 g, 0.127 mol) in DMF (10 ml) is stirred at 80°C. for one hour. After returning to 40-50° C., the mixture is dilutedwith water (200 ml) and stirred for 10 minutes. The precipitate obtainedis filtered off, washed on the filter with water (4 times with 25 ml)and then dried at ambient temperature. A white solid (7.92 g, yield 64%)with a melting point of 161° C. is obtained. The molar purity is 91% (¹HNMR).

No. δ ¹H (ppm) δ ¹³C (ppm) 1 10.45  194.2 2 — 131.5 3 — 139.5 4 2.4419.6 5 7.04 131.2 6 — 142.5 7 2.19 19.5 8 — 131 9 — 139.5 10 2.34 14.611 5.02 42.5 12 6.24 116.9 13 6.59 125.9 14 — 143.5 15 2.32 12.7

II.2-4—Synthesis of2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzaldehyde Oxime

An aqueous hydroxylamine solution (809 g, 0.134 mol, 50% in water,Aldrich) in EtOH (10 ml) is added to a solution of2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzaldehyde (20.3g, 0.084 mol) in EtOH (110 ml) at 40° C. The reaction medium is stirredat a temperature of 50 to 55° C. for 2.5 hours. After returning to 23°C., the precipitate obtained is filtered off, washed twice on the filterwith an EtOH/H₂O (10 ml/15 ml) mixture and dried under atmosphericpressure at ambient temperature for 15 to 20 hours. A white solid (19.57g, yield 91%) with a melting point of 247° C. is obtained. The molarpurity is greater than 87% (¹H NMR).

No. δ ¹H (ppm) δ ¹³C (ppm) 1 2.31 12.7 2 — 143.4 3 6.58 125.8 4 6.22116.9 5 4.97 43.2 6 — 129.3 7 — 136.2 8 2.23 20.2 9 6.97 130 10 — 137.311 2.15 19.1 12 — 129.1 13 — 136.1 14 2.11 15.9 15 8.25 147.4 OH 11.11 —

II.2-5—Synthesis of2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile Oxide

An aqueous solution of NaOCl (4% of active chlorine, Aldrich, 49 ml) isadded dropwise over 5 minutes to a mixture of2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzaldehyde oxime(8.80 g, 0.034 mol) in CH₂Cl₂ (280 ml) at 6° C. The temperature of thereaction medium is maintained between 6° C. and 8° C. The reactionmedium is subsequently stirred at 8° C. to 21° C. for 2 hours. Theorganic phase is separated. The organic phase is washed with water (3times with 50 ml). After concentrating under reduced pressure(temperature of the bath=22-23° C., 220 mbar), petroleum ether (10 ml)is added, the solvent is evaporated down to 8-10 ml and the solution ismaintained at −18° C. for 10-15 hours, so as to obtain a precipitate.The precipitate is filtered off, washed on the filter with theCH₂Cl₂/petroleum ether (2 ml/6 ml) mixture and then with petroleum ether(2 times 10 ml), and finally dried under atmospheric pressure at ambienttemperature for 10-15 hours. A white solid (5.31 g, yield 61%) with amelting point of 139° C. is obtained. The molar purity is greater than95 mol % (¹H NMR).

No. δ ¹H (ppm) δ ¹³C (ppm) 1 2.3  12.6 2 — 143.6 3 6.59 126.1 4 6.27117.1 5 4.99 43 6 — 130.6 7 — 140.7 8 2.16 19.2 9 7.12 129.9 10 — 141 112.34 20 12 — 112.1 13 — NI 14 — 140.8 15 2.28 17.7

II.3-Grafting of the 1,3-dipolar Compound2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile Oxide

Use is made of the modifying agent obtained according to the proceduredescribed above with a molar purity of 93 mol %.

The SBR before modification contains 25% of styrene units and 58% of1,2-units of the butadiene part.

The 2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrileoxide (0.58 g, 2.26 mmol) is incorporated in 50 g of SBR on an open mill(external mixer at 30° C.). 0.5 g of antioxidantN-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine is subsequentlyincorporated. The mixture is homogenized in 15 turnover passes.

This compounding phase is followed by a heat treatment at 120° C. for 10minutes under a press at a pressure of 10 bar.

Analysis by ¹H NMR made it possible to determine a molar degree ofgrafting of 0.23% and a molar grafting yield of 83%.

The quantification of the functional group by NMR is carried out byintegrating an Hb proton of the unit below:

-   -   CH (b) located at 6.25 ppm relating to the SBR matrices

II.4—Synthesis of the 1,3-dipolar Compound2,4,6-trimethyl-3-((2-methyl-1H-benzo[d]imidazol-1-yl)methyl)benzonitrileOxide II.4-1—Synthesis of 2-(chloromethyl)-1,3,5-trimethylbenzene

The synthesis is identical to that described in section II.2-1.

II.4-2—Synthesis of 3-(chloromethyl)-2,4,6-trimethylbenzaldehyde

The synthesis is identical to that described in section II.2-2.

II.4-3—Synthesis of2,4,6-trimethyl-3-((2-methyl-1H-benzo[d]imidazol-1-yl)methyl)benzaldehyde

A mixture of aldehyde (11.9 g, 60.5 mmol), 2-methylbenzimidazole (8.00g, 60.5 mmol) and potassium carbonate (6.27 g, 45.4 mmol) in DMF(dimethylformamide, 15 ml) is stirred at 80° C. for one hour and at 90°C. for three hours. The mixture is subsequently diluted with water (600ml). The organic phase is extracted with EtOAc (3 times 150 ml) andwashed with water (4 times 75 ml). The solvents are evaporated underreduced pressure (36° C. (T_(bath))) to result in a brown oil. Thelatter is crystallized from petroleum ether 40/60 (15 ml) and ethylacetate (20 ml).

A solid (11.70 g, 40.0 mmol, yield 66%) with a melting point of 118° C.is obtained. The molar purity is 70%, EtOAc—5% (¹H NMR).

Solvent: DMSO No. δ ¹H (ppm) δ ¹³C (ppm) 1 7.45 118.0 2 7.01 120.5 36.93 121.2 4 6.79 109.6 5 / 134.9 6 / 142.1 7 / 151.8 8 2.38 14.1 9 5.4242.6 10 / ~131 11 / 139.4 12 2.28 15.1 13 / 131.7 14 10.44  194.3 15 /142.4 16 ~2.44  19.8 17 7.04 131.2 18 / ~141.8 19 2.18 20.3

II.4—Synthesis of2,4,6-trimethyl-3-((2-methyl-1H-benzo[d]imidazol-1-yl)methyl)benzaldehydeoxime

A hydroxylamine solution (6.14 g, 62.9 mmol, 50% in water, Aldrich) inEtOH (20 ml) is added to a solution of aldehyde (11.5 g, 39.4 mmol) inEtOH (80 ml) at 35° C. The reaction medium is stirred at 48-50° C. for3.5 hours. The reaction medium is subsequently cooled down to 10-15° C.and the precipitate obtained is filtered off, washed on the filter witha mixture of ethanol and water (twice with 5 ml and 10 ml mixture) andthen dried under atmospheric pressure at ambient temperature for 15-20hours.

A solid (7.95 g, 25.9 mmol, yield 66%) with a melting point of 248° C.is obtained. The molar purity is greater than 80% (¹H NMR).

No. δ ¹H (ppm) δ ¹³C (ppm) 1 7.43 117.8 2 7.01 120.3 3 6.91 121 4 6.78109.6 5 / 134.9 6 / 142 7 / 151.7 8 2.37 14 9 5.37 43.1 10/11/13/18 /between 129.3 and 136.2 12 2.06 16.3 14 8.24 147.3 15 / 137.1 16 2.2320.3 17 6.96 130.1 19 2.12 19.6

II.4-5—Synthesis of2,4,6-trimethyl-3-((2-methyl-1H-benzo[d]imidazol-1-yl)methyl)benzonitrileoxide

An aqueous solution of NaOCl (6% of active chlorine) (25.4 ml) is addeddropwise over 6-8 minutes to a solution of oxime (6.20 g, 20.2 mmol) indichloromethane (150 ml) cooled down to 5° C. The reaction medium isstirred for 4.5 hours until an emulsion is formed at 10° C. The organicphase is separated and washed with water (3 times with 25 ml). Afterevaporation of the solvent under reduced pressure (T_(bath) 22-23° C.)until crystallization occurs, petroleum ether (40/60) (10 ml) anddichloromethane (4 ml) are added. The suspension is stirred for 10-15minutes and the precipitate is filtered off, washed on the filter withthe CH₂Cl₂/petroleum ether (2 ml/4 ml) mixture and with petroleum ether(40/60) (6 ml), and finally dried under atmospheric pressure at ambienttemperature for 10-15 hours.

A white solid (4.85 g, 15.9 mmol, yield 79%) with a melting point of142° C. is obtained. The molar purity is greater than 71% (¹H NMR).

The crude product (4.4 g) is redissolved in acetone (100 ml), thissolution is then poured into water (500 ml) and the suspension isstirred for 5-10 minutes. The precipitate is filtered off, washed on thefilter with water (200 ml) and dried under atmospheric pressure atambient temperature for 10-15 hours.

A white solid (3.82 g, 12.6 mmol, yield 62%) with a melting point of136.5-137.5° C. is obtained with a purity of 94 mol % by ¹H NMR.

No. δ ¹H (ppm) δ ¹³C (ppm) 1 7.45 118.2 2 7.02 120.7 3 6.95 121.2 4 6.81109.6 5 / 134.7 6 / 141.9 7 / 151.7 8 2.36 13.9 9 5.39 42.8 10 / 130.511 / between 140.2 and 140.6 12 2.24 18.0 13 / 112.3 14 / Undetected 15/ 140.9 16 2.34 19.9 17 / 130.2 18 / between 140.2 and 140.6 19 2.1 19.7Solvent: DMSO

II.5—Grafting of the 1,3-dipolar Compound2,4,6-trimethyl-3-(2-methyl-1H-benzo[d]imidazol-1-yl)methyl)benzonitrileOxide

A grafted isoprene unit is represented in the figure below:

Use is made of the 1,3-dipolar compound obtained according to theprocedure described in section II.4.

The synthetic polyisoprene (IR) before modification contains 98% byweight of cis-1,4-units.

The 1,3-dipolar compound is incorporated in a proportion of 1.35 g per100 g of IR on an open mill (external mixer at 30° C.). 1 g ofantioxidant N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine issubsequently incorporated per 100 g of IR. The mixture is homogenized in12 turnover passes.

This compounding phase is followed by a heat treatment at 120° C. for 10minutes under a press at a pressure of 10 bar.

Analysis by ¹H NMR made it possible to determine a molar degree ofgrafting of 0.20% and a molar grafting yield of 71%.

II.6—Synthesis of the 1,3-dipolar CompoundN-(4-((1H-imidazol-1-yl)methyl)benzylidene)aniline Oxide (Va)

This compound can be prepared according to the following reactionscheme:

II.6-1—Synthesis of Ethyl 4-(chloromethyl)benzoate

A mixture of 4-chloromethylbenzoic acid (10.64 g, 0.062 mol), DMF (70mg, catalytic amount) and SOCl₂ (25 ml, 0.346 mol) is heated at 75° C.for 2 hours. The brown solution is evaporated under reduced pressure at30° C. for 1.5 hours. 12.9 g of a brown oil containing a small amount ofa solid are obtained. After filtration, anhydrous ethanol (60 ml) isadded all at once. The temperature of the reaction medium immediatelyrises up to 40° C. The solution obtained is subsequently brought toreflux (T_(bath) 95° C.) for 3 hours. The reaction is monitored by ¹HNMR (disappearance of the Cl—CH₂ —C₆H₄ signal at 5.8 ppm,solvent—CDCl₃). A yellow oil (11.40 g, yield 92%) is obtained afterconcentrating under reduced pressure (40° C./15-20 mbar). The molarpurity is greater than 93% (¹H NMR).

No. δ ¹H (ppm) δ ¹³C (ppm) 1 1.29 14.3 2 4.28 61.2 3 / 165.8 4 / 130.9 57.95 130.1 6 7.48 129.2 7 / 143.2 8 4.68 45.7 Solvent: d₆-acetone

II.6-2—Synthesis of Ethyl 4-((1H-imidazol-1-yl)methyl)benzoate

A mixture of ethyl 4-(chloromethyl)benzoate (13.55 g, 0.068 mol),imidazole (4.62 g, 0.068 mol) and K₂CO₃ (12.48 g, 0.090 mol) in DMF (100ml) is heated at 115° C. (T_(bath)) for 3-4 hours. After cooling underan inert atmosphere (nitrogen), the reaction medium is maintained atambient temperature for 10-12 hours. The yellow precipitate formed isfiltered off and washed twice with DMF (30 ml). Concentrating thesolvent under reduced pressure at 70-80° C. makes it possible to obtainapproximately 22 g of brown oil which contains DMF.

The crude reaction product is dissolved in CH₂Cl₂ (150 ml) and thenconcentrated under reduced pressure at 70-80° C. The organic phase isextracted three times with CH₂Cl₂ and the combined organic phases arewashed with water. A brown oil (8.00 g, yield 51%) is obtained. Themolar purity is greater than 81% (¹H NMR). The product was used withoutadditional purification.

No. δ ¹H (ppm) δ ¹³C (ppm) 1 1.28 14.4 2 4.27 61.2 3 — 165.9 4 —129.1(?) 5 7.92 130.3 6 7.29 127.9 7 — 143.5 8 5.29 50.1 9 7.05 119.6 106.89 129.7 11 7.63 129.4

II.6-3—Synthesis of 4-((1H-imidazol-1-yl)methyl)phenylmethanol

A solution of LiAlH₄ (1.50 g, 0.039 mol) in anhydrous THF (230 ml) iscooled to −60° C. A solution of ethyl4-((1H-imidazol-1-yl)methyl)benzoate (7.80 g, 0.028 mol, 81 mol %) inanhydrous THF (100 ml) is added under argon over 15 minutes. Thereaction medium is stirred at −60° C. for 1 hour and then at ambienttemperature for 10-12 hours. Water (20 ml) is added dropwise (anexothermic reaction). The precipitate formed is filtered off and thefiltrate is concentrated under reduced pressure. The crude productobtained is dissolved in CH₂Cl₂ (100 ml) in order to precipitateinsoluble materials. After filtering and concentrating under reducedpressure, a yellow oil (4.96 g, yield 93%) is obtained. The molar purityis greater than 85% (¹H NMR).

No. δ ¹H (ppm) δ ¹³C (ppm) 1 4.45 62.5 2 / 141.8 3 7.26 ~126.6 4 7.17127.0 5 / 139.7 6 5.10 49.2 7 7.10 119.0 8 6.87 128.1 9 7.70 136.8Solvent: d₆-DMSO

II.6-4—Synthesis of 4-((1H-imidazol-1-yl)methyl)benzaldehyde

A mixture of MnO₂ (6.88 g, 0.079 mol) and4-((1H-imidazol-1-yl)methyl)phenylmethanol (4.57 g, 0.021 mol, 85 mol %by ¹H NMR) in CHCl₃ (180 ml) is stirred at reflux temperature for 4hours. The reaction medium is cooled down to ambient temperature and iskept stirred at this temperature for 10-12 hours. The insoluble productsare filtered off and the filtrate is concentrated under reducedpressure. A yellow oil (3.78 g, yield 98%) is obtained afterconcentrating under reduced pressure. The molar purity is greater than81% (¹H NMR).

No. δ ¹H (ppm) δ ¹³C (ppm) 1 7.37 136.8 2 6.88 129.1 3 6.74 118.6 4 5.0249.4 5 / 142.4 6 7.07 126.7 7 7.62 129.4 8 / 135.2 9 9.74 190.7 Solvent:CDCl₃

II.6-5—Synthesis of Phenylhydroxylamine

Phenylhydroxylamine was synthesized according to the procedure describedin Org. Syntheses Coll. Vol. 1, p. 445, 1941; Org. Syntheses Coll. Vol.3, p. 668, 1955.

II.6-6—Synthesis of N-(4-((1H-imidazol-1-yl)methyl)benzylidene)anilineOxide

A solution of the aldehyde (3.48 g, 0.015 mol, 81 mol % by ¹H NMR) andphenylhydroxylamine (2.86 g, 0.026 mol) in anhydrous ethanol (20 ml) isstirred at 60° C. (T_(bath)) for 2 hours and subsequently at ambienttemperature for 12 hours. The yellow precipitate is filtered off (0.249g, containing the expected product). Water (30 ml) is added to thefiltrate with vigorous stirring. The yellow precipitate then formed isfiltered off after stirring for 20 minutes and is washed with a mixtureof EtOH (10 ml) and water (20 ml) and then with water (50 ml). The twoportions of solid are combined and dried under atmospheric pressure atambient temperature for 10-12 hours. A yellow solid (3.71 g, yield 89%)with a molar purity of greater than 82% (¹H NMR) is obtained. Anadditional purification is applied by stirring at ambient temperaturefor 1.5 hours, filtering, washing on the filter with 50 ml of ethylether and drying at ambient temperature for 2 days.

A yellow solid (3.04 g, yield 78%) with a melting point of 115-116° C.is obtained. The molar purity is greater than 88% (¹H NMR).

No. δ ¹H (ppm) δ ¹³C (ppm) 1 7.72 137.3 2 6.87 128.5 3 7.15 119.4 4 5.250 5 / 139.9 6 7.3 127.1 7 8.4 128.8 8 / 130.3 9 8.44 132.8 10 / 148.111 7.84 121.2 12 ~7.48 128.9 13 129.7 Solvent: d₆-DMSO

II.7-Preparation of the Rubber Compositions

The g-SBR and g-IR elastomers are used in the preparation of the rubbercompositions g-SBR-C and g-IR-C. The SBR and IR elastomers which wereused to prepare the grafted g-SBR and g-IR elastomers are used in theunmodified form in order to constitute the elastomer matrix of thecontrol compositions SBR-C and IR-C respectively.

The formulations (in phr) of the compositions are described in Table(I). The compositions g-SBR-C and g-IR-C are in accordance with theinvention. The compositions SBR-C and IR-C are respective controlcompositions of the compositions g-SBR-C and g-IR-C.

These compositions are manufactured in the following way: the elastomer,the silica, the coupling agent and also the various other ingredients,with the exception of the vulcanization system, are successivelyintroduced into an internal mixer (final degree of filling:approximately 70% by volume), the initial vessel temperature of which isapproximately 110° C. Thermomechanical working (non-productive phase) isthen carried out in one stage, which lasts approximately 5 min to 6 min,until a maximum “dropping” temperature of 160° C. is reached. Themixture thus obtained is recovered and cooled and then sulphur and anaccelerator of sulphenamide type are incorporated on a mixer(homofinisher) at 23° C., everything being mixed (productive phase) foran appropriate time (for example between 5 and 12 min).

TABLE (I) SBR-C g-SBR-C IR-C not in in not in g-IR-C in Compositionaccordance accordance accordance accordance SBR (1) 100 — — — g-SBR (2)— 101 — — IR (3) — — 100 — g-IR (4) — — — 101 Carbon black 3 3 3 3 N234Silica (5) 55 55 55 55 Silane (6) 5.5 5.5 5.5 5.5 Antioxidant (7) 1.51.5 1 1 Antioxidant (8) 1 — 1.5 0.5 Antiozone wax 1 1 1 1 ZnO 2.7 2.72.7 2.7 Stearic acid 2.5 2.5 2.5 2.5 Sulphenamide 1.8 1.8 2 2 (9)Sulphur 1.5 1.5 1.3 1.3 (1) SBR: SBR with 25% of styrene units and 56%of 1,2-units of the butadiene part (2) g-SBR: SBR modified according tothe synthesis described above in the preceding section II-3. (3) IR:polyisoprene comprising 98% by weight of cis-1,4-units (4) g-IR: IRmodified according to the synthesis described above in the precedingsection II-5. (5) silica: Zeosil 1165 MP from Rhodia (HDS type) (6)TESPT (Si69 from Degussa) (7) 2,2,4-trimethyl-1,2-dihydroquinoline (8)N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine from Flexsys (9)N-cyclohexyl-2-benzothiazolesulphenamide (Santocure CBS from Flexsys)

The compositions thus obtained are subsequently calendered, either inthe form of plaques (with a thickness ranging from 2 to 3 mm) or thinsheets of rubber, for the measurement of their physical or mechanicalproperties, or in the form of profiled elements which can be useddirectly, after cutting and/or assembling to the desired dimensions, forexample as semi-finished products for tyres, in particular for treads.

The crosslinking is carried out at 150° C. The crosslinking time,t′_(c)(90), is the time necessary for the torque of the composition toreach 90% of the maximum torque of the composition. The torques of thecomposition are measured at 150° C. with an oscillating disc rheometer,according to Standard DIN 53529—Part 3 (June 1983). t′_(c)(90) isdetermined according to Standard NF T 43-015 for each of thecompositions.

II.8—Characterization Tests—Results

Tensile Tests:

These tensile tests make it possible to determine the elasticitystresses. Unless otherwise indicated, they are carried out in accordancewith French Standard NF T 46-002 of September 1988. Processing thetensile recordings also makes it possible to plot the curve of modulusas a function of the elongation. At first elongation, the nominal secantmodulus, calculated by reducing to the initial cross-section of the testspecimen, (or apparent stress, in MPa) is measured at 100% elongation,denoted ASM100.

All these tensile measurements are carried out under the standardtemperature conditions (23±2° C.) according to Standard NF T 46-002.

Dynamic Properties:

The dynamic properties are measured on a viscosity analyser (MetravibVA4000) according to Standard ASTM D 5992-96. The response of a sampleof vulcanized composition (cylindrical test specimen with a thickness of4 mm and a cross-section of 400 mm²), subjected to a simple alternatingsinusoidal shear stress, at a frequency of 10 Hz, under standardtemperature conditions (23° C.) according to Standard ASTM D 1349-99 or,as the case may be, at a different temperature (100° C.), is recorded. Astrain amplitude sweep is carried out from 0.1% to 100% (outward cycle)and then from 100% to 0.1% (return cycle). The results made use of arethe complex dynamic shear modulus (G*) at 25% strain, the loss factortan(δ) and the difference in modulus (ΔG*) between the values at 0.1%and 100% strain (Payne effect). For the return cycle, the maximum valueof tan(δ) observed, denoted tan(δ)max, is indicated.

The results are recorded in Table (II) below.

TABLE (II) Properties in the Composition cured state SBR-C g-SBR-C IR-Cg-IR-C ASM100 at 23° C. 2.83 3.19 1.84 3.72 tan(δ)max at 23° C. 0.280.17 0.23 0.08 ΔG* at 23° C. 4 0.93 3.27 0.59 G* at 100° C. 1.61 1.631.35 1.45 tan(δ)max at 100° C. 0.13 0.08 0.13 0.06

The compositions g-SBR-C and g-IR-C exhibit, at 23° C., a modulus ASM100at 23° C. which is much greater than that of the respective controlcompositions SBR-C and IR-C. This increase in stiffness in the curedstate is obtained although a very significant decrease in the hysteresisat 23° C. is also observed for g-SBR-C and g-IR-C, in comparison withtheir respective controls SBR-C and IR-C. The increase in the stiffnessin the cured state is all the more remarkable as the fall in hysteresisis very strong.

As good road behaviour of a tyre is generally associated with a highstiffness in the cured state of the composition which constitutes itstread, this result foretells good road behaviour of a tyre having atread comprising a g-SBR-C or g-IR-C composition.

Furthermore, it is observed that the compositions according to theinvention g-SBR-C and g-IR-C retain a level of stiffness in the curedstate at 100° C. comparable to that of the respective controlcompositions SBR-C and IR-C. These results presage a temperatureversatility of the rubber composition in accordance with the invention.This is because it may be expected that a tread containing thecomposition g-SBR-C or g-IR-C will make it possible for the tyre to havea road behaviour at least just as good as would be had by the controlcomposition SBR-C or IR-C, during more extreme rolling conditions, inparticular for sports car tyres rolling at high-speed.

The invention claimed is:
 1. A process for modifying, by a graftingreaction, an unsaturated polymer which exhibits at least oneunsaturation, the process comprising reacting a 1,3-dipolar compoundwith the at least one unsaturation of the unsaturated polymer, whereinthe 1,3-dipolar compound is of formula (I):Q-A-B  (I), wherein Q comprises a dipole containing at least onenitrogen atom, wherein A is an atom or a group of atoms connecting Q toB, and wherein B comprises a ring of formula (II):

wherein three of four symbols Z, Y, R, and R′ are identical ordifferent, each representing an atom or a group of atoms, it beingpossible for Z and Y to form, together with carbon atoms to which theyare attached, a ring, and a fourth of the four symbols Z, Y, R, and R′denotes a direct attachment to A.
 2. The process according to claim 1,wherein R′ denotes a direct attachment to A.
 3. The process according toclaim 2, wherein Z and Y are each a hydrogen atom.
 4. The processaccording to claim 2, wherein Z and Y form the ring together with thecarbon atoms to which they are attached.
 5. The process according toclaim 1, wherein R represents a hydrogen atom or a carbon-based groupwhich can contain at least one heteroatom.
 6. The process according toclaim 5, wherein R is an alkyl group containing from 1 to 12 carbonatoms.
 7. The process according to claim 1, wherein A is an aliphaticgroup or an aromatic group containing up to 20 carbon atoms which cancontain at least one heteroatom.
 8. The process according to claim 7,wherein A is an alkylene group containing from 1 to 20 carbon atoms oran arylene group.
 9. The process according to claim 1, wherein thecompound is selected from the group consisting of nitrile oxides,nitrile imines, and nitrones.
 10. The process according to claim 9,wherein Q contains a —C≡N→O unit.
 11. The process according to claim 10,wherein Q comprises a unit of formula (III):

wherein four of five symbols R₁ to R₅ are identical or different, eachbeing an atom or a group of atoms, and a fifth of the five symbols R₁ toR₅ denotes a direct attachment to A, and wherein neither of R₁ and R₅ isH.
 12. The process according to claim 11, wherein R₁, R₃, and R₅ areeach an alkyl group of 1 to 6 carbon atoms.
 13. The process according toclaim 12, wherein the compound is2,4,6-trimethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrile oxideor 2,4,6-triethyl-3-((2-methyl-1H-imidazol-1-yl)methyl)benzonitrileoxide.
 14. The process according to claim 9, wherein Q contains a—C═N(→O) unit.
 15. The process according to claim 14, wherein Qcomprises a unit of formula (IV) or (V):

wherein Y₁ is an aromatic group containing from 6 to 20 carbon atoms oran aliphatic group, and wherein Y₂, comprising a direct attachment to A,is an aliphatic group or an aromatic group comprising, on its aromaticnucleus, the direct attachment to A.
 16. The process according to claim14, wherein the compound is of formula (IVa), (IVb), (Va), or (Vb):


17. The process according to claim 1, wherein the 1,3-dipolar compoundis reacted according to a stoichiometry of between 0 and 3 molarequivalents of imidazole ring per 100 moles of monomer unitsconstituting the polymer.
 18. The process according to claim 1, whereinthe unsaturated polymer is a diene polymer.
 19. The process according toclaim 18, wherein the diene polymer is an essentially unsaturated dieneelastomer selected from the group consisting of a polybutadiene, apolyisoprene, a butadiene copolymer, an isoprene copolymer, and amixture thereof.
 20. A polymer obtained by the process according toclaim 1.